The present invention relates to a camshaft drive for an internal-combustion V-engine having at least one overhead camshaft for each cylinder bank, driving wheels which are arranged on the camshafts and each driven by output wheels which are non-rotatably mounted on a crankshaft. A first output wheel in a driving connection with the camshafts on one cylinder bank and a second output wheel is in a driving connection with the camshafts of the other cylinder bank.
In German Patent Document DE-33 47 638 C, an internal-combustion engine of the above-described type is disclosed which has cylinder banks that are arranged in a V-shape with respect to one another and whose respective two overhead camshafts are driven by a single double-row timing chain. Because of the overlapping of the driving wheels of two adjacent camshafts respectively and because of the offset of the cylinder banks with respect to one another in the longitudinal direction of the internal-combustion engine, it is not possible to use identical camshafts.
It is known from German Patent Document DE 88 13 425 U to use two identical cylinder heads in an internal-combustion V-engine, which cylinder heads are rotated with respect to one another by 180 degrees. Because of the drive of a camshaft of each cylinder bank on a front end of the internal-combustion engine, these camshafts have different constructions.
An object of the present invention is to provide a camshaft drive in an internal-combustion engine of the above-described type, which has a number of different components that is as small as possible and which optimally utilizes an existing installation space.
This and other objects are achieved by the present invention which provides a camshaft drive for an internal-combustion V-engine that has at least two cylinder banks, and comprises at least one overhead camshaft for each cylinder bank, a crankshaft, and a first output wheel non-rotatably mounted on the crankshaft and drivingly connected with the camshaft of one cylinder bank and a second output wheel non-rotatably mounted on the crankshaft and drivingly connected with the camshaft of the other cylinder bank. First and second driving wheels are mounted on the camshafts and are driveably coupled to at least one of the first and second output wheels. An additional output is arranged between the first and second output wheels. The cylinder banks are offset from one another in a longitudinal direction of the V-engine, and the first and second output wheels are separated from one another in the longitudinal direction on the crankshaft by a distance that is approximately identical to the offset of the cylinder banks. All of the driving wheels are identical parts.
In internal-combustion engines with cylinder banks that are arranged at an arbitrary angle in a V-shape with respect to one another, this camshaft drive permits the use of identical camshafts for both cylinder banks. This advantage applies particularly to internal-combustion engines with several camshafts for each cylinder bank. Identical driving wheels, which are constructed as identical parts, are arranged on all camshafts. The use of identical camshafts is achieved by an offset between the output wheels which are arranged on the crankshaft and are assigned to the cylinder banks, which corresponds to the offset of the cylinder banks with respect to one another. In certain embodiments of the invention, the installation space on the crankshaft which is created between the output wheels is used for the arrangement of a gearwheel which drives an oil pump arranged at a distance to the crankshaft or coaxial with respect to this gearwheel.
Other objects, advantages and novel features of the present invention will become apparent from the following detailed description of the invention when considered in conjunction with the accompanying drawings.